     /** string **/
     String.prototype.format = function(args) {
      var result = this;
      if (arguments.length > 0) {
          if (arguments.length == 1 && typeof (args) == "object") {
              for (var key in args) {
                  if(args[key]!=undefined){
                      let reg = new RegExp("({" + key + "})", "g");
                      result = result.replace(reg, args[key]);
                  }
              }
          }
          else {
              for (var i = 0; i < arguments.length; i++) {
                  if (arguments[i] != undefined) {
                      let reg= new RegExp("({)" + i + "(})", "g");
                      result = result.replace(reg, arguments[i]);
                  }
              }
          }
      }
      return result;
  }